It seems that it's actually 3 times the size of the sun rather than 1/3 While GRS 1915+105 is a black-hole pipsqueak with a mass only 14 times that of our sun,

It seems that it's actually 3 times the size of the sun rather than 1/3 While GRS 1915+105 is a black-hole pipsqueak with a mass only 14 times that of our sun, IGR J17091-3624 is tinier still, estimated to be a mere three times as massive as Ol' Sol